Method for diagnosing pheochromocytoma



United States Patent Office 3,373,081 Patented Mar. 12, 1968 3,373,081 METHOD FOR DIAGNOSING PHEOCHROMOCYTOMA Albert Sjoerdsma, Bethesda, Md., and Karl Engelman,

Boston, Mass, assignors to the United States of America as represented by the Secretary of the Department of Health, Education, and, Welfare No Drawing. Filed Apr. 28, 1964, Ser. No. 363,282 4 Claims. (Cl. 167-845) ABSTRACT OF THE DISCLOSURE A new, accurate method for disgnosing pheochromocytoma which comprises determining the pressor response in systolic blood pressure to intravenous injection of tyramine. The baseline systolic blood pressure of a patient is determined, an intravenous injection of 250 to 1000 micrograms of tyramine is administered, and a rise in systolic blood pressure greater than 20 mm. of mercury is observed if pheochromocytoma is present.

This invention relates to a new method of diagnosis. More specifically, this invention relates to a new and more accurate method for diagnosing pheochromocytoma which comprises determining the pressor response in systolic blood pressure to an intravenous injection of 250 to 1000 micrograms of a pharmaceutically acceptable salt of tyramine l-hydroxyphenethylamine) based on the free base whereby a pressor response greater than 20 mm. of mercury in systolic blood pressure shows the presence of said disease. This invention also relates to compositions for such use.

'Pheochromocytoma is defined as a catecholamineproducing tumor of the adrenal medulla and other tissues. Its tissue contains. the catecholamine hormones, epinephrine, adrenaline or norepinephrine (noradrenaline) or both and its presence is associated with many signs and symptoms, particularly paroxysmal hypertension. Other terms such as chromafiinoma and paraganglioma, have been used in the past but pheochromocytoma is the preferred designation and refers to a hormonally-active tumor.

Although measurements of catecholamines and their metabolites in the urine provide the most reliable means of diagnosing pheochromocytoma, the specialized nature of the procedures involved are such that reliable measurements are unavailable to many physicians. Thus, considerable reliance must still be placed on pharmacologic aids to diagnosis. These are of two types: vesopressor provocative tests and the vasodepressor blocking tests.

Though several diiferent compounds have been used in such tests, only the original provocative agent, histamine and the blocking test employing phenotolamine have retained favor among clinicians. The morbidity associated with intravenous injection of histamine is well known. Flushing and severe throbbing headache, while transient, are very disturbing to the patient, and the use of this agent is contraindicated in aged patients and those with coronary disease or asthma. In the presence of pheochromocytoma alarming pressor effects and severe morbidity may be encountered with the use of histamine, and at least two deaths have been reported. For these reasons, some physicians do histamine tests reluctantly,

or not at all.

We have found a new andsafe and more effective method for the diagnosis of pheochromocytoma, a method which is effective even when older methods give false results.

The object of the present invention is a safe and reliable provocative agent whose use is not attended by significant morbidity or hazard. A theoretical basis for such a test seems to exist if one assumes that increased tissue stores of catecholamines occur at sympathetic nerve endings in patients with pheochromocytoma as a result of uptake from the blood. If this is so, an exaggerated pressor response might be expected following injection of a socalled indirectly-acting sympathomimetic compound, i.e., one whose effects are mediated by release of norepinephrine at nerve endings. The compound of this type which we have found useful is tyramine. It is the essence of this invention that We find tyramine offers the advantage of a more predictable pressor response and an absence of undesirable side effects.

In the method of this invention, tyramine hydrochloride is conveniently prepared in a concentration of 10 mg tyramine base (12.66 mg. tyramine hydrochloride) per ml. water with 0.1% sodium metabisulfite as preservative and sterilized by filtration by Dr. Joseph Gillelli, Pharmaceutical Development Service of the National Institutes of Health. This preparation is stable for at least one year when kept in sealed dark bottles at 4 C. Just prior to use, the tyramine is diluted to a concentration of 200 to 1000 g. per ml. with sterile isotonic saline. Other pharmaceutically acceptable salts of tyramine such as the sulfate, nitrate, phosphate, citrate,'hydrobromide and the like can equally well be used. Similarly, in the preparation of the compositions for use in this invention, other pharmaceutically acceptable preservatives, benzylalcohol, phenol, chlorobutanol or a mixture of the methyl and propyl esters of p-hydroxybenzoic acid, may be used.

The compositions for use in this invention comprise a sterile isotonic aqueous solution of a pharmaceutically acceptable salt of tyramine, the concentration of tyramine base being of the order of 250 to 1000 micrograms per milliliter. Ordinarily, and preferably, it is a 1 cc. or 2 cc.

unit dose of 1000 g./ml. concentration. Thus, a 1 cc.

vial contains just enough for one 1.0 mg. injection. This is contemplated as the standard one injection test dose. If a series of doses are to be used, the 2 cc. vial of l rug/ml. concentration permits a 250 pg., a 500 pg., and a 1 mg. dose to be given successively by successive Withdrawal of A1, /2 and 1 cc. from a 2 cc. vial.

The response to tyramine injection is studied with the subject resting in a quiet room. An intravenous infusion of 5 percent dextrose in water is started in one arm, and indirect blood pressures using a mercury manometer and inflatable cuff are determined in the other arm. The blood pressure is measured every two minutes until it stablilizes (usually 10-20 minutes), and then single injections of placebo (isotonic sodium chloride solution) or graded doses of tyramine are given through a three-way stopcock at the proximal end of the infusion tubing, followed by rapid flushing of the material into the patient with 5-10 ml. of 5 percent of dextrose in water. The blood pressure is recorded every thirty seconds after injection until the systolic pressure returns to baseline. The blood pressure may then be recorded every minute for an additional 10-15 minutes after which another injection may be given.

Before doses of tyramine are given to the subjects, it is desirable to establish that there is no response to the injection of the placebo. This usually requires no more than one or two placebo injections. Once this is achieved, increasing doses of tyramine are given, the initial dose being 250 g. The usual doses employed are 250, 500, 1000, 1500 and 2000 g. with higher doses given in 1000 g. increments to a limit of 6000 g. as permitted by the response in the blood pressure. Because of their increased pressor responsiveness to tyramine, four of five patients tested with phcochromocytoma were given no more than 1000 g. and the fifth patient received a maximum dose of only 1500 g.

When a minimally etfe'ctive pressor dose is established cytoma had blood pressure levels in the range of 118/80 in each subject, varying doses are given in randomized mm. Hg to 168/ 122 mm. Hg at the time of testing with fashion to achieve reproducible responses. Dose response tyramine. It may also be seen that the urinary excretions curves are constructed for each subject using the average of the eatecholamines and their metabolites were diagof at least two peak systolic pressor responses at each level 5 nostic of pheochromocytoma in each case. Patients 1 of dosage. Changes in diastolic blood pressure are inand 2 had their primary tumors resected, but at the. consistent and irrelevant. time of this study, they had histologically proven malig- Inthe present study a systolic blood pressure rise of nant pheochromocytoma with widespread metastases. 7 greater than 20 mm. Hg following intravenous injection Patients 3 and 4 had benign tumors which were subseof 1000 ,ug. or less of tyramine base occurs only in 10 quently removed with apparent resultant cure. The fifth cases of pheochromocytoma. Specificity is indicated by patient, 5, is presumed to have a benign tumor, but surgithe lesser responses to tyramine in hypertensive and cal exploration has been deferred because of medical connormotensive subjects without pheochromocytoma and traindications. No patient with pheochromocytoma was the conversion of tyramine pressor responses to normal receiving anti-hypertensive medications at the time of our in two patients by removal of their tumors. Furthermore, study, although large doses of intramuscular reserpine the tyramine responsiveness is shown to be normal in were discontineud two days before testing in patient 2. four hypertensive patients who had borderline or false Patients 1, 2 5 have each 736611 managed successfully positive histamine tests. for longer than a year by oral administration of phenoxy- When tyramine has been administered by this protocol benzamine. outlined, there have been no serious pressor episodes, and The patients with essential hypertension separated into only minimal discomfort in the form of palpitations was two groups on the basis of their control blood pressures experienced by a few of the patients. In all cases that at the time of the studies: -(a) mild hypertension; 12 have a pressor response" of greater than 20 mm. Hg to this patients with untreated labile or sustained hypertension dose of tyramine, further evaluation of the diagnosis of in the range of 140 to 200 mm. Hg systolic and less pheochromocytoma should be pursued by specific chemithan 100 mm. Hg diastolic, and (b) severe hypertension; cal analysis of the urine for the catecholamines or their nine patients with untreated sustained hypertension metabolites. greater than 200/ 110 mm. Hg. 7

This invention can be illustrated by the following de- The data obtained by these tests are summarized in tailed example of its use and the examples of composithe series of tables which follow in which TableI shows tions to be used. the catecholamine data on five patients with the disease and Table II shows the normal tyramine responses in Example 1 tests. Table 111 shows the typical response to tyramine from a patient with pheochromocytoma. Table IV shows Three groups of hospitalized subjects were studied: the ranges of response d th m an responses of groups hypertensive patients with borderline or false histamine 1) five female patients, ages 12 to 71 years, with pheoof individuals in various categories, including normal chromocytoma, (2) 16 male and five female patients, persons, hypertensives and those with pheochromocytoma. ages 16 to 57 years, with essential hypertension of vary- In Table V is summarized the dose response curves of ing severity, and (3) five male and six female healthy these categories and the detaileddose response of persons volunteers, ages 17 to 43 years, with normal blood preswith the tumor while Table VI gives the dose response sure. of individuals before and after surgical excision of the As shown in Table I, the patients with pheochromotumor.

TABLE I. DATA IN FIVE PATIENTS WITH PHEOCHROMOCYTOMA Patient (age, sex) Control Blood NE g/day) E g/day) NMN-l-MN (mg./ VMA (mg/day) Pressure (mm.Hg V V V 7 day) 167/118 524 47 3. 5 15. 6 155/108 3, 140 N.S. 16. 9 52. 2 68/122, 1, 900 NS. 6 20. 7 2 (115/80) 4 (38, F) 118/80, 2, 700 1,800 122 600 2 (110/80) 5 (71, F) 120/88 72 625 10.8 40 Upper Limit of Normal 80 20 V 7 1.3 p 7 6.0

1 Average control blood pressure during the pretreatment tyrarnine response tests. 2 Numbers in parenthesis represent average control blood pressures during post-operative tyramme response tests. NoTE.NE=nnc0njugated norepinephrine, E=unconjugated epinephrine, N MN MN =nonnetanephrme+matanephrine, VMA =vvanilmandelic acid, N.S.=not significant; significant value for E cannot be determined when rt constitutes less than 5% of the total daily catecholamine excretion.

TABLE IL-NORMAL TYRAMINE RESPONSES IN HYPERTENSIVE PATIENTS WITH BORDE-RLINE OR FALSE POSITIVE HISTAMIN E TESTS Systolic and Diastolic Maximum Rise in Blood Pressure (mm. Hg) Urinary Catecholamine Excretion g/hr.) (normal 4.0)

Patient (age, sex) Histamine Dose Tyramino Dose Cold Pressor Test Control Alter Histamine, 25 g. g. 500 g. 1,000 4g. 2 hr. sample False Positive:

7 (47, M) /38 0/0 0/0 56/28 2. 0 3. 1 Borderline Po pre etl a ee ba e of compound.

TABLE TIL-TYPICAL RESPONSE TO TYRAMI-NE FOR PATIENT WITH PHEOCHROMOCYTOMA (PATIENT NO. 2)

Time from 600 g Tyramine Blood pressure (systolic),

TABLE IV.PRESSOR RESPONSES FOR INDIVIDUALS IN EACH GROUP TO 1,000 g. TYRAMINE Change in Blood Pressure, Group mm. Hg

Range Mean (1) Pheochromocytoma (5 patients) 20-62 42 (2) Mild Hypertensives (12 patients) -15 4. (3) Severe Hypertensives (9 patients) 013 7. 0 (4) Normal Persons (11 subjects) 0-8 2. 8

TABLE V.--DOSE RESPONSE 1N MM. Hg BLOOD PRESSURE IN C REASE Dose, g. Tyramine Base Patients:

1 43 62 40 50 18 34 29 45 5. 16 20 40 u. Hyp e chromoeytoma 2. 5 6 11. 14. 7 Average of 21 patients (Range)- (010) (0-15) (0-24) (4-32) Normal: Average of 11 persons- 1. 2. 8 6. 8. 8

Range (0-5) (0-8) (0-16) (0-22) TABLE VI.-COMPARISON OF DOSE RESPONSE BEFORE AND AFTER SURGICAL REMOVAL OF TUMOR [Expressed in mm. Hg of increase in systolic pressure] Patient No. 1 Patient No. 2 T amine yr (pg Before After Before After Example 2.Composiii0ns (A) To a solution of mg. of tyramine base (as the hydrochloride) in 10 cc. of isotonic sodium chloride is added a mixture of 0.15 mg. of methyl p-hydroxy benzoate and 0.2 mg. of propyl p-hydroxybenzoate. The solution is sterilized by filtration and diluted to 100 ml. With sterile isotonic sodium chloride solution. It is then used to fill sterile 1 cc. and 2 cc. ampules which are then sealed under sterile conditions.

('B) The composition of part A is prepared, using the citrate, sulfate, hydrobromide, and phosphate of tyramine.

(C) The composition of part A is prepared, using 0.9 mg. of benzylalcohol or 0.5 mg. of phenol in place of the mixture of p-hydroxybenzoates.

(D) The composition of part A is prepared without the p-hydroxybenzoate preservative mixture. Upon being sealed into the ampules, the solution can be stored for a long period of time without deterioration.

We claim:

1. A method of diagnosing pheochromocytoma which comprises determining in a patient the pressor response in systolic blood pressure to intravenous injection of 250- 1000 micrograms of a pharmaceutically acceptable salt of tyramine, based on the free base, said tyramine being in an isotonic saline solution of 500-1000 micrograms per ml. concentration, whereby a pressor response greater than 20 mm. of mercury in systolic blood pressure shows presence of said disease.

2. The method of claim 1, wherein said saline solution of tyramine also contains a pharmaceutically acceptable preservative.

3. The method of claim 2 in which said preservative is sodium metabisulfite.

4. A method of diagnosing pheochromocytoma which comprises, in combination, the steps of:

(1) determining in a patient the base-line systolic blood pressure;

(2) successively injecting intravenously to said patient a solution of a water-soluble pharmaceutically acceptable tyramine salt, said injection comprising respectively 250 micrograms, 500 micrograms and 1000 micrograms of tyramine based on the free base; and (3) observing pressor response of greater than 20 mm. of mercury in systolic blood pressure over the said base-line blood pressure.

References Cited Remingtons Practice of Pharmacy, 12th Ed. 1961, Mack Pub. Co., Easton, Pa., p. 964, 1290-2.

Sollmann: A Manual of Pharmacology, 8th Ed. 1957, W. B. Saunders Co., Philadelphia, pp. 91, 513-4.

Smith, J.: Pharm & Expt. Therapeutics, vol. 139, March 1963, pp. 321-329.

Mash-ford: PSEBM, vol. 11, 1962, pp. 308-311.

ALBERT T. MEYERS, Primary Examiner. A. FAGELSON, Assistant Examiner. 

